Preparation and Corrosion Properties of TiO2-SiO2-Al2O3 Composite Coating on Q235 Carbon Steel

The TiO2-SiO2-Al2O3 composite coatings were fabricated on the surfaces of Q235 carbon steel via the sol-gel method to improve its corrosion resistance. The effects of the sintering temperature and the layer number on the corrosion performances were explored. The coating morphology, microstructure and phase composition were analyzed by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). Friction wear experiment, immersion experiment, and electrochemical impedance spectroscopy techniques were used to investigate the corrosion properties of the coatings as well. The results show that the sample with the TiO2-SiO2-Al2O3 coatings sintered at 850 °C are more uniform and denser and have better corrosion resistance and wear resistance than the other coatings. The Rp value of the 3 L coating sintered at 850 °C was about 114 kΩ·cm2, and the average friction coefficient was about 0.36.